Tehran is downplaying a 25-year prison sentence against an Iranian-American who was convicted in an alleged Iranian-backed plot to assassinate Saudi Arabia’s ambassador to the United States.

Foreign Ministry spokesman Abbas Araqchi said on Iranian state television that “convicting an innocent person in such a way has no legal value and is merely a political move” by the U.S. federal court.

Manssor Arbabsiar, a naturalized U.S. citizen who also holds an Iranian passport, was convicted after admitting he conspired with Iranian military officials to try to kill Saudi Ambassador Adel al-Jubeir at a Washington restaurant in September 2011.